AMPA antagonists and a method of treatment

ABSTRACT

The present patent application discloses compounds having formula (I) or a pharmaceutically acceptable salt thereof wherein R 1  is hydrogen, alkyl or benzyl; X is O or NOR 2 , wherein R 2  is hydrogen, alkyl or benzyl; Y is N--R 4  wherein R 4  is hydrogen, OH or alkyl; n is 0 or 1; R 6  is phenyl, naphthyl, thienyl, pyridyl, all of which may be substituted one or more times with substituents selected from the group consisting of halogen, CF 3 , NO 2 , amino, alkyl, alkoxy and phenyl; A is a ring of five to seven atoms fused with the benzo ring at the positions marked a and b. The compounds are useful in the treatment of cerebrovascular disorders. ##STR1##

The present application is a division of our prior-filed application Ser. No. 08/545,763, filed Jan. 4, 1996, now U.S. Pat. No. 5,780,493, which is a 35 USC 371 application based on PCT/EP94/01492, filed May 9, 1994.

The present invention relates to novel ring fused glutamate antagonists, a method of treatment therewith, pharmaceutical compositions comprising the compounds and to a method of preparing the novel compounds of the invention.

OBJECT OF THE INVENTION

It is an object of the present invention to provide novel glutamate antagonists which are useful in the treatment of disorders or diseases in mammals, including a human, and especially in the treatment of disorders or diseases which are responsive to the blockade of the glutamate and/or aspartate receptors of such mammal.

Another object of the present invention is to provide a method of treating disorders or diseases of mammals, including a human, responsive to the blockade of glutamic and aspartic acid receptors which comprises administering to a mammal in need thereof a compound of the invention.

A third object of the present invention is to provide novel pharmaceutical compositions for the treatment of disorders or diseases of mammals, including a human, responsive to the blockade of glutamic and aspartic acid receptors.

Other objectives of the present invention will be apparent to the skilled person hereinafter.

BACKGROUND OF THE INVENTION

Excessive excitation by neurotransmitters can cause the degeneration and death of neurons. It is believed that this degeneration is in part mediated by the excitotoxic actions of the excitatory amino acids (EAA), glutamate and aspartate, at the N-methyl-D-aspartate (NMDA), the alfa-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor, and the kainate receptor. This excitotoxic action is responsible for the loss of neurons in cerebrovascular disorders such as cerebral ischemia or cerebral infarction resulting from a range of conditions, such as thromboembolic or haemorrhagic stroke, cerebral vasospasm, hypoglycaemia, cardiac arrest, status epilepticus, perinatal asphyxia, anoxia such as from near-drowning, pulmonary surgery and cerebral trauma as well as lathyrism, Alzheimer's, and Huntington's diseases.

The compounds of the present invention may also be useful in the treatment of Amyotrophic Lateral Sclerosis (ALS), schizophrenia, Parkinsonism, epilepsy, anxiety, pain and drug addiction.

SUMMARY OF THE INVENTION

The invention then, inter alia, comprises the following, alone or in combination:

A compound having the formula ##STR2## or a pharmaceutically acceptable salt thereof wherein R¹ is hydrogen, alkyl or benzyl;

X is O or NOR², wherein R² is hydrogen, alkyl or benzyl;

Y is N--R⁴ wherein R⁴ is hydrogen, OH or alkyl;

n is 0 or 1;

R⁶ is

phenyl,

naphthyl,

thienyl,

pyridyl,

all of which may be substituted one or more times with substituents selected from the group consisting of halogen, CF₃, NO₂, amino, alkyl, alkoxy and phenyl;

A is a ring of five to seven atoms fused with the benzo ring at the positions marked a and b, and formed by the following bivalent radicals:

a-NR¹² --CH₂ --CH₂ -b

a-CH₂ --CH₂ --NR¹² -b

a-CH₂ --NR¹² --CH₂ -b,

a-CH₂ --CH₂ --NR¹² --CH₂ -b,

a-CH₂ --NR¹² --CH₂ --CH₂ -b,

a-CH₂ --CH₂ --CH₂ --NR¹² -b,

a-NR¹² --CH₂ --CH₂ --CH₂ -b,

a-CH₂ --CH₂ --NR¹² --CH₂ --CH₂ -b,

a-CH₂ --CH₂ --CH₂ --NR¹² --CH₂ -b,

a-CH₂ --NR¹² --CH₂ --CH₂ --CH₂ -b,

a-CH₂ --CH₂ --CH₂ --CH₂ --NR¹² -b,

a-NR¹² --CH₂ --CH₂ --CH₂ --CH₂ -b,

wherein

R¹² is hydrogen, CH₂ CH₂ OH, or alkyl;

and a compound as above having the formula ##STR3## or a pharmaceutically acceptable salt thereof; wherein X, Y, n, R¹, R⁶, and R¹² have the meanings set forth above;

and a compound as above having the formula ##STR4## or a pharmaceutically acceptable salt thereof; wherein X, Y, n, R¹, R⁶, and R¹² have the meanings set forth above;

and a compound as above having the formula ##STR5## or a pharmaceutically acceptable salt thereof; wherein X, Y, n, R¹, R⁶, and R¹² have the meanings set forth above;

and a compound as above having the formula ##STR6## or a pharmaceutically acceptable salt thereof; wherein X, Y, n, R¹, R⁶, and R¹² have the meanings set forth above;

and further a method of treating a disorder or disease of a mammal, including a human, which disorder or disease is responsive to the blockade of glutamic and/or aspartic acid receptors, which comprises administering to a patient in need thereof an effective amount of a compound as any above in unit dosage form;

and the method as above wherein lathyrism, Alzheimer's disease, Huntington's diseases, ALS, schizophrenia, Parkinsonism, epilepsy, anxiety, pain, drug addiction, or cerebrovascular disorders are treated;

and a pharmaceutical composition comprising a therapeutically-effective amount of a compound as any above together with a pharmaceutically-acceptable carrier;

and the use of a compound as any above for the manufacture of a medicament for the treatment a disorder or disease of a mammal, including a human, which disorder or disease is responsive to the blockade of glutamic and/or aspartic acid receptors;

and a method of preparing a compound as any above comprising the step of:

a) reacting a compound having the formula ##STR7## wherein A, a, b R¹, and R⁶ have the meanings set forth above, with NH₂ OR², wherein R² has the meaning set forth above, or with a reactive derivative thereof, to form a compound of the invention; or

b) reacting a compound having the formula ##STR8## wherein A, a, b R¹, and R⁶ have the meanings set forth above, with oxalic acid or a reactive derivative thereof, to form a compound of the invention.

Examples of pharmaceutically acceptable addition salts include inorganic and organic acid addition salts such as the hydrochloride, hydrobromide, phosphate, nitrate, perchlorate, sulphate, citrate, lactate, tartrate, maleate, fumarate, mandelate, benzoate, ascorbate, cinnamate, benzenesulfonate, methanesulfonate, stearate, succinate, glutamate, glycollate, toluene-p-sulphonate, formate, malonate, naphthalene-2-sulphonate, salicylate and the acetate. Such salts are formed by procedures well known in the art.

Other acids such as oxalic acid, while not in themselves pharmaceutically acceptable, may be useful in the preparation of salts useful as intermediates in obtaining compounds of the invention and their pharmaceutically acceptable acid addition salts.

Halogen is fluorine, chlorine, bromine, or iodine.

Alkyl means a straight chained or branched chain of from one to six carbon atoms or cyclic alkyl of from three to seven carbon atoms, including but not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, hexyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl; methyl, ethyl, propyl and isopropyl are preferred groups.

Alkoxy is O-alkyl, wherein alkyl is as defined above.

Amino is NH₂ or NH-alkyl or N-(alkyl)₂, wherein alkyl is as defined above.

The compounds of this invention may exist in unsolvated as well as in solvated forms with pharmaceutically acceptable solvents such as water, ethanol and the like. In general, the solvated forms are considered equivalent to the unsolvated forms for the purposes of this invention.

Some of the compounds of the present invention exist in (+) and (-) forms as well as in racemic forms. Racemic forms can be resolved into the optical antipodes by known methods, for example, by separation of diastereomeric salts thereof, with an optically active acid, and liberating the optically active amine compound by treatment with a base. Another method for resolving racemates into the optical antipodes is based upon chromatography on an optical active matrix. Racemic compounds of the present invention can thus be resolved into their optical antipodes, e.g., by fractional crystallization of d- or l- (tartrates, mandelates, or camphorsulphonate) salts for example. The compounds of the present invention may also be resolved by the formation of diastereomeric amides by reaction of the compounds of the present invention with an optically active activated carboxylic acid such as that derived from (+) or (-) phenylalanine, (+) or (-) phenylglycine, (+) or (-) camphanic acid or by the formation of diastereomeric carbamates by reaction of the compounds of the present invention with an optically active chloroformate or the like.

Additional methods for the resolvation of optical isomers, known to those skilled in the art may be used, and will be apparent to the average skilled in the art. Such methods include those discussed by J. Jaques, A. Collet, and S. Wilen in "Enantiomers, Racemates, and Resolutions", John Wiley and Sons, New York (1981).

Starting materials for the processes described in the present application are known or can be prepared by known processes from commercially available chemicals.

The products of the reactions described herein are isolated by conventional means such as extraction, crystallization, distillation, chromatography, and the like.

BIOLOGICAL ACTIVITY In Vitro Activity (Receptor Affinity)

The compounds of the invention exhibit valuable biological properties because of their strong excitatory amino acid (EAA) antagonizing properties at the AMPA ((RS)-alfa-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) binding site.

The compounds of the present invention exhibit binding affinity for the AMPA receptor as described by T. Honore et al., Neuroscience Letters 54, 27-32 (1985) with IC₅₀ values from the nanomolar to the lower micro molar range.

                  TABLE 1                                                          ______________________________________                                         Compound       IC.sub.50                                                       ______________________________________                                         Compound 3     0.6 μM                                                       Compound 9     0.2 μM                                                       Compound 10     0.15 μM                                                     Compound 13    0.1 μM                                                       ______________________________________                                    

Also compounds of the present invention when administered i.v. or i.p. in the in vivo AMPA seizure test as described below inhibit the clonic seizures induced by AMPA.

In Vivo Activity (AMPA-Induced Clonic Seizures)

AMPA given icv (intracerebroventricular) (15 μg/kg) NMRI to mice induces clonic seizures which should be inhibited by non-NMDA receptor antagonists. Method: Test compound was given i.v. 5 min (or p.o. 30 min) before a 0.3 μg icv administration of AMPA to 10 female NMRI mice (weighing 24-26 g) per dose. The number of mice experiencing clonic seizures within the next 5 min was noted. An ED₅₀ value was calculated as the dose inhibiting 50% of the mice from having clonic seizures.

                  TABLE 2                                                          ______________________________________                                         Compound       ED.sub.50                                                       ______________________________________                                         Compound 10    5 mg/kg                                                         ______________________________________                                    

Several of the compounds of the present invention have been tested in the standard 2 vessel occlution test in gerbils for global anti-ischemic activity. All of the compounds tested have been found to have profound activity in this test set-up, which in the scientific community is thought to be a reliable test set-up of global ischemia, such as for example seen in patients following cardiac arrest, myocardial infarction and high risk surgery.

PHARMACEUTICAL COMPOSITIONS

While it is possible that, for use in therapy, a compound of the invention may be administered as the raw chemical, it is preferable to present the active ingredient as a pharmaceutical formulation.

The invention thus further provides pharmaceutical formulations comprising a compound of the invention or a pharmaceutically acceptable salt or derivative thereof together with one or more pharmaceutically acceptable carriers therefor and, optionally, other therapeutic and/or prophylactic ingredients. The carrier(s) must be "acceptable" in the sense of being compatible with the other ingredients of the formulation and not deleterious to the recipient thereof.

Pharmaceutical formulations include those suitable for oral, rectal, nasal, topical (including buccal and sub-lingual), vaginal or parenteral (including intramuscular, sub-cutaneous and intravenous) administration or in a form suitable for administration by inhalation or insufflation.

The compounds of the invention, together with a conventional adjuvant, carrier, or diluent, may thus be placed into the form of pharmaceutical compositions and unit dosages thereof, and in such form may be employed as solids, such as tablets or filled capsules, or liquids such as solutions, suspensions, emulsions, elixirs, or capsules filled with the same, all for oral use, in the form of suppositories for rectal administration; or in the form of sterile injectable solutions for parenteral (including subcutaneous) use. Such pharmaceutical compositions and unit dosage forms thereof may comprise conventional ingredients in conventional proportions, with or without additional active compounds or principles, and such unit dosage forms may contain any suitable effective amount of the active ingredient commensurate with the intended daily dosage range to be employed. Formulations containing ten (10) milligrams of active ingredient or, more broadly, 0.1 to one hundred (100) milligrams, per tablet, are accordingly suitable representative unit dosage forms.

The compounds of the present invention can be administrated in a wide variety of oral and parenteral dosage forms. It will be obvious to those skilled in the art that the following dosage forms may comprise, as the active component, either a compound of the invention or a pharmaceutically acceptable salt of a compound of the invention.

For preparing pharmaceutical compositions from the compounds of the present invention, pharmaceutically acceptable carriers can be either solid or liquid. Solid form preparations include powders, tablets, pills, capsules, cachets, suppositories, and dispersible granules. A solid carrier can be one or more substances which may also act as diluents, flavouring agents, solubilizers, lubricants, suspending agents, binders, preservatives, tablet disintegrating agents, or an encapsulating material.

In powders, the carrier is a finely divided solid which is in a mixture with the finely divided active component.

In tablets, the active component is mixed with the carrier having the necessary binding capacity in suitable proportions and compacted in the shape and size desired.

The powders and tablets preferably contain from five or ten to about seventy percent of the active compound. Suitable carriers are magnesium carbonate, magnesium stearate, talc, sugar, lactose, pectin, dextrin, starch, gelatin, tragacanth, methylcellulose, sodium carboxymethylcellulose, a low melting wax, cocoa butter, and the like. The term "preparation" is intended to include the formulation of the active compound with encapsulating material as carrier providing a capsule in which the active component, with or without carriers, is surrounded by a carrier, which is thus in association with it. Similarly, cachets and lozenges are included. Tablets, powders, capsules, pills, cachets, and lozenges can be used as solid forms suitable for oral administration.

For preparing suppositories, a low melting wax, such as admixture of fatty acid glycerides or cocoa butter, is first melted and the active component is dispersed homogeneously therein, as by stirring. The molten homogenous mixture is then poured into convenient sized molds, allowed to cool, and thereby to solidify.

Formulations suitable for vaginal administration may be presented as pessaries, tampons, creams, gels, pastes, foams or sprays containing in addition to the active ingredient such carriers as are known in the art to be appropriate.

Liquid form preparations include solutions, suspensions, and emulsions, for example, water or water-propylene glycol solutions. For example, parenteral injection liquid preparations can be formulated as solutions in aqueous polyethylene glycol solution.

The compounds according to the present invention may thus be formulated for parenteral administration (e.g. by injection, for example bolus injection or continuous infusion) and may be presented in unit dose form in ampoules, pre-filled syringes, small volume infusion or in multi-dose containers with an added preservative. The compositions may take such forms as suspensions, solutions, or emulsions in oily or aqueous vehicles, and may contain formulatory agents such as suspending, stabilising and/or dispersing agents. Alternatively, the active ingredient may be in powder form, obtained by aseptic isolation of sterile solid or by lyophilisation from solution, for constitution with a suitable vehicle, e.g. sterile, pyrogen-free water, before use.

Aqueous solutions suitable for oral use can be prepared by dissolving the active component in water and adding suitable colorants, flavours, stabilizing and thickening agents, as desired.

Aqueous suspensions suitable for oral use can be made by dispersing the finely divided active component in water with viscous material, such as natural or synthetic gums, resins, methylcellulose, sodium carboxymethylcellulose, or other well known suspending agents.

Also included are solid form preparations which are intended to be converted, shortly before use, to liquid form preparations for oral administration. Such liquid forms include solutions, suspensions, and emulsions. These preparations may contain, in addition to the active component, colorants, flavours, stabilizers, buffers, artificial and natural sweeteners, dispersants, thickeners, solubilizing agents, and the like.

For topical administration to the epidermis the compounds according to the invention may be formulated as ointments, creams or lotions, or as a transdermal patch. Ointments and creams may, for example, be formulated with an aqueous or oily base with the addition of suitable thickening and/or gelling agents. Lotions may be formulated with an aqueous or oily base and will in general also contain one or more emulsifying agents, stabilising agents, dispersing agents, suspending agents, thickening agents, or colouring agents.

Formulations suitable for topical administration in the mouth include lozenges comprising the active agent in a flavoured base, usually sucrose and acacia or tragacanth; pastilles comprising the active ingredient in an inert base such as gelatin and glycerin or sucrose and acacia; and mouthwashes comprising the active ingredient in a suitable liquid carrier.

Solutions or suspensions are applied directly to the nasal cavity by conventional means, for example with a dropper, pipette or spray. The formulations may be provided in single or multidose form. In the latter case of a dropper or pipette, this may be achieved by the patient administering an appropriate, predetermined volume of the solution or suspension. In the case of a spray, this may be achieved for example by means of a metering atomising spray pump.

Administration to the respiratory tract may also be achieved by means of an aerosol formulation in which the active ingredient is provided in a pressurized pack with a suitable propellant such as a chlorofluorocarbon (CFC) for example dichlorodifluoromethane, trichlorofluoromethane, or dichlorotetrafluoroethane, carbon dioxide, or other suitable gas. The aerosol may conveniently also contain a surfactant such as lecithin. The dose of drug may be controlled by provision of a metered valve.

Alternatively the active ingredients may be provided in the form of a dry powder, for example a powder mix of the compound in a suitable powder base such as lactose, starch, starch derivatives such as hydroxypropylmethyl cellulose and polyvinylpyrrolidone (PVP). Conveniently the powder carrier will form a gel in the nasal cavity. The powder composition may be presented in unit dose form for example in capsules or cartridges of, e.g., gelatin, or blister packs from which the powder may be administered by means of an inhaler.

In formulations intended for administration to the respiratory tract, including intranasal formulations, the compound will generally have a small particle size for example of the order of 5 microns or less. Such a particle size may be obtained by means known in the art, for example by micronization.

When desired, formulations adapted to give sustained release of the active ingredient may be employed.

The pharmaceutical preparations are preferably in unit dosage forms. In such form, the preparation is subdivided into unit doses containing appropriate quantities of the active component. The unit dosage form can be a packaged preparation, the package containing discrete quantities of preparation, such as packeted tablets, capsules, and powders in vials or ampoules. Also, the unit dosage form can be a capsule, tablet, cachet, or lozenge itself, or it can be the appropriate number of any of these in packaged form.

Tablets or capsules for oral administration and liquids for intravenous administration are preferred compositions.

METHOD OF TREATING

The compounds of this invention are extremely useful in the treatment of central nervous system disorders related to their biological activity. The compounds of this invention may accordingly be administered to a subject, including a human, in need of treatment, alleviation, or elimination of a disorder or disease associated with the biological activity of the compounds. This includes especially excitatory amino acid dependent, including glutamate and/or aspartate dependent psychosis, excitatory amino acid dependent, including glutamate and/or aspartate dependent anoxia, excitatory amino acid dependent, including glutamate and/or aspartate dependent ischemia, excitatory amino acid dependent, including glutamate and/or aspartate dependent Parkinsonism, excitatory amino acid dependent, including glutamate and/or aspartate dependent convulsions and excitatory amino acid dependent, including glutamate and/or aspartate dependent migraine as well as ALS. Suitable dosage ranges are 0.1 to 1000 milligrams daily, 10-500 milligrams daily, and especially 30-100 milligrams daily, dependent as usual upon the exact mode of administration, form in which administered, the indication toward which the administration is directed, the subject involved and the body weight of the subject involved, and further the preference and experience of the physician or veterinarian in charge.

The following nonlimiting examples illustrate the present invention further.

EXAMPLE 1 ##STR9##

A solution of 4-acetamido-2-methyl-2H-1,3-dihydro-isoindole (10 g) and bromine (3.0 g) in trifluoroacetic acid (150 ml) was stirred at 50° C. for 40 hours. The solution was evaporated in vacuo. The residue was dissolved in water (300 ml), and pH was adjusted to neutral with sat. Na₂ CO₃. This treatment afforded a crystalline precipitate of the product, which was collected by filtration. Yield 9 g, mp. 145°-148°.

EXAMPLE 2 ##STR10##

A solution of potassium nitrate (1.78 g, 8.56 mmol) was added slowly to a solution of 5-bromoisoquinoline in 12 mL H₂ SO₄. After stirring for 3 hours the reaction mixture was poured onto ice and neutralized with conc. ammonium hydroxide. The yellow precipitate was extracted with ethyl acetate (3×), and the combined organic layers were washed with saturated NaCl, dried over MgSO₄, filtered and concentrated. The residue was chromatographed on silica gel (40% ethyl acetate in hexane as eluent) to give 5-bromo-8-nitroisoquinoline in 96% yield.

EXAMPLE 3 ##STR11##

A mixture of 5-bromo-8-nitroisoquinoline (0.99 g, 3.91 mmol) and dimethylsulfate (0.41 mL) in anhydrous DMF (20 mL) was heated at 80° C. for 24 hours. After removing the DMF in vacuo, the isoquinoline methylammonium salt was obtained (used without further purification).

In a similar manner the following compound was prepared:

2-ethyl-5-bromo-8-nitroquinolinium ethylsulphate by reaction with diethyl sulphate

EXAMPLE 4 ##STR12##

The isoquinoline salt (3.9 mmol) was dissolved in acetic acid (10 mL) and sodium borohydride (0.15 g, 3.97 mmol) was added. After stirring for 24 h, the reaction mixture was diluted with a mixture of ethyl acetate and water and potassium carbonate was added portionwise to neutralize the acetic acid. The aqueous layer was extracted with ethyl acetate (2×), washed with saturated NaCl, dried over MgSO₄, filtered and evaporated. The residue was chromatographed on silica gel (30% ethyl acetate in hexane as eluent) to give the light sensitive N-methyl 5-bromo-8-nitro-1,2,3,4-tetrahydroisoquinoline (0.47 g, 45% yield).

N-ethyl-5-bromo-8-nitro-1,2,3,4-tetrahydroisoquinoline was prepared according to the same procedure. M.p. 52°-53° C.

EXAMPLE 5 ##STR13##

A mixture of 4-acetamido-7-bromo-2-methyl-2H-1,3-dihydro-isoindole (0.2 g), phenyl boronic acid (137 mg), tetrakis(triphenylphosphine)palladium 0! (26 mg), NaHCO₃, (315 mg) was stirred at reflux temperature in a mixture of water (3.75 ml) and dimethoxyethane (7.5 ml) for 90 min. After cooling to room temperature the reaction mixture was partitioned between EtOAc (25 ml ) and aq. NaOH (2×5 ml 1N). The organic phase was then dried over Na₂ SO₄ and evaporated to give 4-acetamido-7-phenyl-2-methyl-2H-1,3-dihydro-isoindole, mp 160°-62° C.

In a similar manner the following compounds were prepared from the appropriate bromides and boronic acids:

4-acetamido-7-phenyl-2-ethyl-2H-1,3-dihydro-isoindole, mp. 67°-68° C.

4-acetamido-7-(1-naphthyl)-2-methyl-2H-1,3-dihydro-isoindole mp. 260°-62° C.

4-acetamido-5-nitro -7-phenyl-2-methyl-2H-1 ,3-dihydro-isoindole mp. 270°-72° C.

5-acetamido-2-methyl-6-nitro-8-phenyl-1,2,3,4-tetrahydro-isoquinoline mp. 214°-217° C.

2-methyl-5-phenyl-8-nitro-1,2,3,4-tetrahydro-isoquinoline mp 75°-78° C. from reaction between phenyl boronic acid and 5-bromo-2-methyl-8-nitro-1,2,3,4-tetrahydro-isoquinoline.

2-methyl-5-(4-chlorophenyl)-8-nitro-1,2,3,4-tetrahydro-isoquinoline mp 162°-163° C.

2-methyl-5-(4-trifluoromethylphenyl)-8-nitro-1,2,3,4-tetrahydro-isoquinoline mp 133°-134° C.

2-methyl-5-(4-fluorophenyl)-8-nitro-1,2,3,4-tetrahydro-isoquinoline mp 159°-160° C.

EXAMPLE 6 ##STR14##

A mixture of 4-acetamido-7-bromo-2-methyl-2H-1,3-dihydro-isoindole(8 mmol), diethyl(3-pyridyl)borane, tetrakis(triphenylphosphine)palladium (0) (400 mg), powdered potassium hydroxyde (32 mmol) and tetrabutylammonium bromide (4 mmol) was refluxed in THF (50 mL) for 48 hours. The mixture was then cooled to room temperature, whereafter EtOAc (100 mL) was added. The resulting mixture was then filtered through filter aid, and the filtrate was evaporated. The residue was partitioned between water (50 mL) and diethyl ether (25 mL). This treatment afforded a crystalline precipitate of the product which was collected by filtration and washed with water and diethylether, mp. 180°-86° C.

EXAMPLE 7 ##STR15##

4-acetamido-7-phenyl-2-methyl-2H-1,3-dihydro-isoindole(2.6 g) was heated with stirring at 80° C. for 48 hours in sulphuric acid (66%, 25 mL), whereafter the solution was poured onto ice and then neutralized with aq. NaOH. The precipitated product was collected by filtration, and washed with water. Mp. 154°-55° C.

Similar deacetylations gave:

4-amino-7-(1-naphthyl)-2-methyl-2H-1,3-dihydro-isoindole, mp. 145°-48° C.

4-amino-5-nitro -7-phenyl-2-methyl-2H-1,3-dihydro-isoindole, mp 170°-72° C.

5-amino-2-methyl-6-nitro-8-phenyl-1,2,3,4-tetrahydro-isoquinoline, mp. 128°-130° C.

4-amino-7-phenyl-2-ethyl-2H-1,3-dihydro-isoindole hydrochloride, mp. 222°-225° C.

EXAMPLE 8 ##STR16## 4,5-diamino-7-phenyl-2-methyl-2H- 1,3-dihydro-isoindole, mp. 230°-240° C. (decomposes),

5,6-diamino-2-methyl-8-phenyl-1,2,3,4-tetrahydro-isoquinoline, 8-amino-2-methyl-5-phenyl-1,2,3,4-tetrahydro-isoquinoline hydrochloride, mp. 210°-21° C.,

8-amino-2-methyl-5-(4-fluorophenyl)-1,2,3,4-tetrahydro-isoquinoline, mp. 141° C.,

8-amino-2-methyl-5-(4-trifluoromethylphenyl)-1,2,3,4-tetrahydro-isoquinoline, mp. 132°-134° C., and

8-amino-2-methyl-5-(4-chlorophenyl)-1,2,3,4-tetrahydro-isoquinoline hydrochloride, mp. 213°-215° C., were all obtained by hydrogenation using Pd/C as catalysist and ethanol as solvent.

EXAMPLE 9 ##STR17##

A solution of 4,5-diamino-7-phenyl-2-methyl-2H-1,3-dihydro-isoindole (1.1 g) and oxalic acid (1.3 g) in 4N hydrochloric acid (25 mL) was refluxed for two hours. This afforded a crystalline precipitate of the product as the hydrochloride which was collected by filtration. Mp. >300 C. (Compound 1).

In a similar manner 1,4,7,8,9,10-hexahydro-6-phenyl-8-methyl-pyrido 4,3-f!quinoxaline-2,3-dione was prepared. Mp >300° C. (Compound 2)

EXAMPLE 10 ##STR18##

To a 5° C. warm solution of potassium nitrate in sulphuric acid (98%,10 mL) was added neat 1,7,8,9-tetrahydro-8-methyl-6-phenyl-4H-pyrrolo 3,4-f!quinoxaline-2,3-dione(0.2 g). After 1 hour at 5° C. the solution was poured on ice, neutralized and the precipitated product filtered off by suction. The solid was washed with water, mp.>300° C. (Compound 3). The isolated compound is 1,7,8,9-tetrahydro-8-methyl-6-(4-nitrophenyl)-4H-pyrrolo 3,4-f!quinoxaline-2,3-dione. Likewise 8-methyl-5-(4-nitrophenyl)-6,7,8,9-tetrahydro-1H-pyrrolo 3,2-h!isoquinoline-2,3-dione was prepared, mp>300° C. (Compound 4).

EXAMPLE 11 ##STR19##

A mixture of 4-amino-7-phenyl-2-methyl-2H-1,3-dihydro-isoindole (2.0 g, 9 mmol),conc HCl (0.83 ml), 1.5 ml chloral, 10 g of Na₂ SO₄, NH₂ OH (2.0 g) in water (60 mL) was refluxed for two hours, whereafter it was cooled and neutralized with sat. NaHCO₃. The aqueous solution was decanted from the oily residue which was dissolved in methylene chloride (100 mL). This solution was dried over Na₂ SO₄, and the solvent was removed by evaporation. The residue was dissolved in methane sulphonic acid (3 ml) and heated to 120° C. for 30 min. After cooling to ambient temperature the solution was diluted with water (20 mL) and neutralized with sat. Na₂ CO₃. The impure product was filtered off. Pure 7-methyl-5-phenyl-1,6,7,8-tetrahydrobenzo 2,1-b:3,4-c!dipyrrole-2,3-dione mp. 187°-90° C. was obtained after column purification on silica gel using methylene chloride acetone methanol (4:1:1) as eluent.

In a similar manner the following compounds were prepared:

7-ethyl-5-phenyl-1,6,7,8-tetrahydrobenzo 2,1-b:3,4-c!dipyrrole-2,3-dione, mp. >250° C.(decomposes). (Compound 5)

7-methyl-5-(1-naphthyl)-1,6,7,8-tetrahydrobenzo 2,1-b:3,4-c!dipyrrole-2,3-dione-3-oxime in low yield, mp.>300° C. (Compound 6)

7-methyl-5-(3-pyridyl)-1,6,7,8-tetrahydrobenzo 2,1-b:3,4-c!dipyrrole-2,3-dione-3-oxime. NMR (¹ H,500 MHz, 6-D DMSO): 2.5 ppm (3H,S), 3.8 ppm (2H,S), 3.9 ppm (2H,S), 6.5-8.7 ppm (5H aromatic, 1S, 4M), 11.0ppm (1H,S, NH) 13.4 ppm (1H,S,NOH). (Compound 7)

8-methyl-5-phenyl-6,7,8,9-tetrahydro-1H-pyrrolo 3,2-f!isoquinoline-2,3-dione, mp. 280°-82° C. (Compound 14)

8-methyl-5-(4-chlorophenyl)-6,7,8,9-tetrahydro-1H-pyrrolo 3,2-f!isoquinoline-2,3-dione, mp. 225° C. (decomposes). (Compound 15)

8-methyl-5-(4-trifluoromethylphenyl)-6,7,8,9-tetrahydro-1H-pyrrolo 3,2-f!isoquinoline-2,3-dione, mp. 220°-25° C. (Compound 16)

8-methyl-5-(4-fluorophenyl)-6,7,8,9-tetrahydro-1H-pyrrolo 3,2-f!isoquinoline-2,3-dione, mp. 220°-21° C. (Compound 17)

EXAMPLE 12 ##STR20##

A mixture of 7-methyl-5-phenyl-1,6,7,8-tetrahydrobenzo 2,1-b:3,4-c!dipyrrole-2,3-dione (150 mg), NH₂ OH,HCl (75 mg) and Na₂ CO₃ was stirred overnight at room temperature in methanol (5 ml). Water (10 ml) was added, and the precipitated product was filtered off. Mp. >300° C. (Compound 8). The isolated compound is 7-methyl-5-phenyl-1,6,7,8-tetrahydrobenzo- 2,1-b: 3,4-c!dipyrrole-2,3-dione 3-oxime.

In a similar manner were prepared:

8-methyl-5-phenyl-6,7,8,9-tetrahydro-1H-pyrrolo 3,2-h!isoquinoline-2,3-dione 3-oxime, mp 280°-82° C. (Compound 9)

8-methyl-5-(4-nitrophenyl)-6,7,8,9-tetrahydro-1H-pyrrolo 3,2-h!isoquinoline-2,3-dione 3-oxime, mp. >300° C. (Compound 10)

8-methyl-5-phenyl-6,7,8,9-tetrahydro-1H-pyrrolo 3,2-h!isoquinoline-2,3-dione 3-o-methyloxime hydrochloride, mp 284°-90° C. (Compound 11)

7-ethyl-5-phenyl-1,6,7,8-tetrahydrobenzo 2,1-b:3,4-c!dipyrrole-2,3-dione 3-oxime hydrochloride, mp. >300° C. (Compound 12)

8-methyl-5-(4-chlorophenyl)-6,7,8,9-tetrahydro-1H-pyrrolo 3,2-h!isoquinoline-2,3-dione 3-oxime, mp 300°-305° C. (Compound 18)

8-methyl-5-(4-fluorophenyl)-6,7,8,9-tetrahydro-1H-pyrrolo 3,2-h!isoquinoline-2,3-dione 3-oxime, mp 295°-300° C. (Compound 19)

8-methyl-5-(4-trifluoromethylphenyl)-6,7,8,9-tetrahydro-1H-pyrrolo 3,2-h!isoquinoline-2,3-dione 3-oxime, mp 295°-300° C. (Compound 20)

EXAMPLE 13 ##STR21##

Under an atmosphere of nitrogen a mixture of 7-ethyl-5-bromo-1,6,7,8-tetrahydrobenzo 2,1-b:3,4-c!dipyrrole-2,3-dione 3-oxime(0.2 g) and phenyltrimethyltin(0.22 g) was heated to 80° C. in dimethylformamide (2 ml). Then a catalytic amount of Bis- triphenylphosphine!-palladium 2! chloride was added. Stirring at 80° C. was continued for 72 hours, whereafter the solvent was evaporated. The product was obtained by chromatography of the residue on silica gel using EtOAc:MeOH 9:1 as eluent. Mp.>300° C. (Compound 13). The isolated compound is 7-ethyl-5-phenyl-1,6,7,8-tetrahydro-benzo 2,1-b:3,4-c!dipyrrole-2,3-dione 3-oxime. 

We claim:
 1. A compound selected from those having the formula ##STR22## and a pharmaceutically-acceptable salt thereof wherein R¹ is hydrogen, alkyl, or benzyl;X is O or NOR², wherein R² is hydrogen, alkyl, or benzyl; Y is N--R⁴ wherein R⁴ is hydrogen, OH, or alkyl; n is 1; R⁶ isphenyl, naphthyl, thienyl, or pyridyl,all of which may be substituted one or more times with a substituent selected from the group consisting of halogen, CF₃, NO₂, amino, alkyl, alkoxy, and phenyl; A is a ring of five to seven atoms fused with the benzo ring at the positions marked a and b, and formed by one of the following bivalent radicals: a-NR¹² --CH₂ --CH₂ -b a-CH₂ --CH₂ --NR¹² -b a-CH₂ --NR¹² --CH₂ -b, a-CH₂ --CH₂ --NR¹² --CH₂ -b, a-CH₂ --NR¹² --CH₂ --CH₂ -b, a-CH₂ --CH₂ --CH₂ --NR¹² -b, a-NR¹² --CH₂ --CH₂ --CH₂ -b, a-CH₂ --CH₂ --NR¹² --CH₂ --CH₂ -b, a-CH₂ --CH₂ --CH₂ --NR¹² --CH₂ -b, a-CH₂ --NR¹² --CH₂ --CH₂ --CH₂ -b, a-CH₂ --CH₂ --CH₂ --CH₂ --NR¹² -b, and a-NR¹² --CH₂ --CH₂ --CH₂ --CH₂ -b,wherein R¹² is hydrogen, CH₂ CH₂ OH, or alkyl.
 2. A compound of claim 1 selected from those having the formula ##STR23## and a pharmaceutically-acceptable salt thereof; wherein X, Y, n, R¹, R⁶, and R¹² have the meanings set forth in claim
 1. 3. A compound of claim 1 selected from those having the formula ##STR24## and a pharmaceutically-acceptable salt thereof; wherein X, Y, n, R¹, R⁶, and R¹² have the meanings set forth in claim
 1. 4. A compound of claim 1 selected from those having the formula ##STR25## and a pharmaceutically-acceptable salt thereof; wherein X, Y, n, R¹, R⁶, and R¹² have the meanings set forth in claim
 1. 5. A compound of claim 1 selected from those having the formula ##STR26## and a pharmaceutically-acceptable salt thereof; wherein X, Y, n, R¹, R⁶, and R¹² have the meanings set forth in claim
 1. 6. A method of treating a disorder or disease of a mammal, including a human, which disorder or disease is responsive to the blockade of glutamic and/or aspartic acid receptors, said disease or disorder being selected from the group consisting of Alzheimer's disease, Huntington's diseases, ALS, schizophrenia, Parkinsonism, epilepsy, anxiety, pain, drug addiction, and cerebrovascular disorders, which comprises administering to a patient in need thereof an amount of a compound of claim 1 effective for alleviation thereof in unit dosage form.
 7. A pharmaceutical composition comprising a therapeutically-effective amount of a compound of claim 1 together with a pharmaceutically-acceptable carrier.
 8. A method of preparing a compound of claim 1 comprising the step of:reacting a compound having the formula ##STR27## wherein A, a, b, R¹, and R⁶ have the meanings set forth above, with oxalic acid or a reactive derivative thereof, to form a compound of claim
 1. 9. A compound of claim 1 wherein the compound is 1,7,8,9-tetrahydro-8-methyl-6-(4-nitrophenyl)-4H-pyrrolo 3,4-f!quinoxaline-2,3-dione.
 10. A method of claim 6 wherein the compound is 1,7,8,9-tetrahydro-8-methyl-6-(4-nitrophenyl)-4H-pyrrolo 3,4-f!quinoxaline-2,3-dione.
 11. A composition of claim 8 wherein the compound is 1,7,8,9-tetrahydro-8-methyl-6-(4-nitrophenyl)-4H-pyrrolo 3,4-f!quinoxaline-2,3-dione. 